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Sample calculation for computing EPI threshold

Case 1

Consider an office building in a composite climate, operational for 15 hours and 5 days a week.

• GRIHA benchmark for EPI as per Table 3.3 = 90 kWh/m2/year (for an office building operational for 8 hours and 5 days a week in a composite climate)
• Total number of working hours in a day as per Case 1 = 15 hours
• Total number of working days in a week as per Case 1 = 5 days
• Therefore, the final GRIHA benchmark for EPI for Case 1 = 90 × (15 ÷ 8) = 168.75 kWh/m2/year

Case 2

Consider an office building in a composite climate, operational for 16 hours and 7 days a week.

• GRIHA benchmark for EPI as per Table 3.3 = 225 kWh/m2/year (for an office building operational for 24 hours and 7 days a week in a composite climate)
• Total number of working hours in a day as per Case 2 = 16 hours
• Total number of working days in a week as per Case 2 = 7 days
• Therefore, the final GRIHA benchmark for EPI for Case 2 = 90 × (16 ÷ 24) = 150 kWh/m2/year

Case 3

Consider a healthcare facility in a hot and dry climate, operational for 16 hours and 5 days a week.

• GRIHA benchmark for EPI as per Table 3.3 = 250 kWh/m2/year (for a healthcare facility operational for 24 hours and 7 days a week in a hot and dry climate)
• Total number of working hours in a day as per Case 3 = 16 hours
• Total number of working days in a week as per Case 3 = 5 days
• Therefore, the final GRIHA benchmark for EPI for Case 3 = 300 × (16 ÷ 24) × (5 ÷ 7) = 119.05 kWh/m2/year

Case 4

Consider a mixed-use building in a composite climate comprising a healthcare facility (24 hours and 7 days a week), residential building (24 hours and 7 days a week) and an office building (8 hours and 6 days a week).

Case 5

Consider an office building in a composite climate, operational for 18 hours and 6 days a week.

• GRIHA benchmark for EPI as per Table 3.3 = 225 kWh/m2/year (for an office building operational for 24 hours and 7 days a week in a composite climate)
• GRIHA benchmark for EPI as per Table 3.3 = 90 kWh/m2/year (for an office building operational for 8 hours and 5 days a week in a composite climate)
• Total number of working hours in a day as per Case 5 = 18 hours
• Total number of working days in a week as per Case 5 = 6 days
• Therefore, the final GRIHA benchmark for EPI for Case 5 can be calculated as per the two options mentioned below:
• Option 1: 90 × (6 ÷ 5) × (18 ÷ 8) = 243 kWh/m2/year
• Option 2: 225 × (18 ÷ 24) × (6 ÷ 7) = 144.64 kWh/m2/year
• Therefore, the final GRIHA benchmark for EPI for Case 5 is 144.64 kWh/m2/year (consider the more stringent value out of the two aforementioned options).

Notes

• The total occupied days cannot be greater than 6; total occupied hours cannot be greater than 16 for buildings to be considered as a daytime operational building.
• The total occupied days must be 7; total occupied hours cannot be less than 14 for a building to be considered as a 24 × 7 operational building.
• In case a building lies between the aforementioned conditions (such as case 5), then the more stringent EPI value based on the computed options will be considered as the final GRIHA benchmark for EPI.